Colorful Window Boxes

There are a limitless number of window box containers to choose from, including wire troughs, plastic, wood or metal (figure B). When selecting the proper container for your needs, consider the cost, size and weight of the container. These factors affect the installation and the way the water drains during use.

Gardening in a small space successfully demands good soil. Garden soil is probably too heavy for a window box. Select a soil mixture that is lighter and better at retaining moisture.

Moisture is a very important component to successful window box gardening. "One of the keys to window box gardening is not letting the window box dry out," says Swett. "If you can't be home to water frequently, the right potting soil is essential." Swett suggests adding a water-absorbent polymer to help do the job. Always apply a little less than recommended because too much polymer can make the soil texture gummy. Simply sprinkle the polymer into the soil and mix well. Next, add lots of perlite to lighten the soil and encourage drainage. Add a handful of vermiculite to the mix, as well; the volcanic ash adds essential nutrients.

Once you have prepared a good potting soil, choose the appropriate plants. "The first and most important thing to consider when selecting plants is whether they are horticulturally compatible with each other and the conditions," says Swett. Basically, all the plants in the window box need to grow under the same light conditions, water, fertilizer and temperature requirements.

At the end of the season, you'll need to take down the window box and clean it out. If you've used separate containers, however, you probably won't need to do more than squirt the window box with some water and dry thoroughly.